Write validation helpers 

[% IF validation_errors %]
<div class="container validation-errors">
  <div class="row">
    <div class="alert span6">
      <button class="close" data-dismiss="alert">×</button>[% alert %]
      <h2>Data input errors</h2>
      <ul>
      [% FOREACH err = validation_errors %]
        <li>[% err | html %]</li>
      [% END %]
      </ul>
    </div>
  </div>
</div>
[% END %]